Magnetic ionic liquids (MILs), combines the general properties of ionic liquid with magnetic properties, are starting to attract interest in the field of propane/propylene separation and CO2 capture. Solubility data of propane, propylene, cyclopropane and CO2 in magnetic ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate [bmim] [FeCl4] at temperatures of (303, 313, 323, 333, 343) K and pressures up to 3300 kPa were determined in the present work. The relative expanded uncertainty of solubility measurement is estimated to be less than 4% with a level of confidence of 95%. The Henry's constants for the four gases in [bmim][FeCl4] and selectivity of C3H6/C3H8 in [bmim][FeCl4] were calculated. And the thermodynamic properties of solvation concerned about the Gibbs energy (AsolGx), the enthalpy (Asoil-in and the entropy (AsoiSw) of solvation were also obtained to offer knowledge for understanding the progress of gases dissolved in [bmim][FeCl4]. The experimental results were correlated with a modified KK equation and NRTL equation. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.